I agree with Dennis Wish's statements in his January 19, 2000, email message
on the Subject matter, in particular, the wording: "I often wondered if we,
as a professional community, know enough about natural disasters to stick our
necks out to define just how well a structure will perform. Had we started
to advertise the idea that our codes were performance based before the
Northridge earthquake occurred, would we have been surprised to find
ourselves embroiled in numerous lawsuits for the damage that occurred?"
In July 1996, I wrote a letter, which was published in the SEAONC Newsletter
and copies of this letter were posted, at least twice, on the SEAOSC List
Service with the Subject: "And The Buildings Will Not Even Catch a Cold."
In this letter, I attempted to point out the possible professional legal
liabilities that would go along with the "implied warranties" that could be
inferred with the use of performance based seismic design.
In the 1999 SEAOC Blue Book is an Appendix I, Tentative Guidelines for
Performance Based-Seismic Engineering" written by the SEAOC Ad Hoc
Subcommittee, Robert Bachman, Chair. and et al. I was a member of this Ad
Hoc Subcommittee and was successful in providing the printed wording in
Section 1A-1.4, Limitations, page 368, and Section 1B-1.5, Statement of
Limited Reliability, page 392, pointing out "However, there is no guarantee
that the design performance objective will actually be achieved." and "It
must be recognized that the reliability of PBSE is limited and that design
performance objectives can not be achieved with certainty."
I am attempting to get similar wording in the ASCE/FEMA 273 and ASCE/FEMA 310
Standards, which are under development.
I have been lead to believe that FEMA resisted inclusion of wording similar
to the above 1997 Blue Book wording in FEMA 273, October 1997.. The
strongest wording the authors of FEMA 273 could get in FEMA 273, Section 1.1,
Purpose was: "An engineer can use this document to help a building owner
select seismic protection criteria when the owner's risk reduction efforts
are purely voluntary. The engineer can also use the document for the design
and analysis of seismic rehabilitation projects. HOWEVER, THIS DOCUMENT
SHOULD NOT BE CONSIDERED TO BE A DESIGN MANUAL, TEXTBOOK, OR HANDBOOK."
In fairness, FEMA did allow the wording buried in FEMA 273, Section 1.3.4,
Technical Content, in the middle of a very long paragraph, which reads:
"Compliance with the Guidelines should therefore not be considered a
guarantee of the specified performance." In my judgment, this long
paragraph should have its own section heading, such as Section 1.3.5
,"Limitations" or "Statement of Limited Reliability" instead of burying the
above statement in the middle of a long paragraph where it probably will be
Hopefully, the public will not be lead to believe that if the provisions of
FEMA 273, ASCE/FEMA 273 and ASCE/FEMA 310 are followed "Their buildings will
not even catch a cold."
By copy of this subject email message to the original authors of FEMA 273 and
present authors of ASCE/FEMA 273 and ASCE/FEMA 310, I respectfully bring to
their attention some suggestions on how these documents can be improved and
hopefully, attempt to minimize the professional legal liability that goes
with the use of performance-based seismic design.
Frank E. McClure January 20, 2000